Recently, requirements for comfortability of living spaces and energy saving have been increasing; for this reason, the shapes of target objects required for thermal insulation properties tend to become complex, and the spaces for disposing thermal insulation materials tend to be reduced. For this reason, a thermal insulation material having not only enhanced thermal insulation performance but also a lower thickness has been required.
As an attempt for an enhancement in thermal insulation performance of a thermal insulation material using a foamed resin, for example, a plate-shaped foam containing at least one layer of metal thin film on the surface and/or the inside of a polypropylene-based resin foam has been proposed in Patent Literature 1.
Moreover, aerogels are known as a material having low thermal conductivity and having thermal insulation properties. For example, Patent Literature 2 describes production of a solvent containing gel sheet by a continuous method.